Latch



A. F. LICKTEIG May 16, 1950 LATCH Filed May 19, 1947 ALBERT F LiCKTEiC-r 31 QQMM Ms Q Amoanexs 21/ 8 /1 Ya e. 8.

Patented May 16, 1950 LATCH Albert F. Li'ckteig,.'Grand Rapids, Mich, assignor "to National Brass- Company, Grand Rapids, -Mi'ch., a corporation of Michigan Application May 19, 1947, Serial 'No. 748,948

8 Claims. 1

The present invention is concerned and directed to latches for doors of the general type shown in Patent #l,8'71,633 to Herman 'ler Meer, issued August 16, 1932.

"The present latch is an improvement upon the Ter Meer latch, particularly 'in'that it may be appreciably shortened in overall length. Latches of the kind to which this invention is directed must be economically produced at lowest cost of manufacture, have few parts, be very simply and rapidly assembled and, as they are used in'larg'e measure upon screen doors, or other doors having light weight door frames of limited strength, as much of the vertical stile of the door frame, at the free edge of a hinged door where the latch is mounted, must be retained in order not to so greatly reduce the cross sectional area of the stile, where the latch is mounted on the door, that it will break across or otherwise fracture under the service to which the door is subjected. The outside diameter of the assembled latch must be reduced to a minimum in order to retain as much of the thickness dimension of the vertical door stile as possible and, what is of more importance, the latch must be of a short length as possible and still be successful, in order that the full thickness of the door, from the inner end to the opening in which the latch is installed, to the inner edge of the vertical door shall be as much as posstble.

Light weight doors require latches so that the door may be closed by a minimum force to auto matically push back, or retract, the latch bolt as it rides over a striking plate on the door jamb, until the bolt enters a keeper opening usually made in the strike plate. This requires that 'a yielding force of minimum strength upon the latch bolt only shall be efiective when the door is closed. This may be supplied by a spring of light strength for keeping the bolt from accidental retracting and disengaging from the keeper, and a greater strength of springis required than is effective for the bolt alone, tobe overcome when the bolt is manually retracted in unlatchingthe door. This is shown in the Ter Meer patent, above mentioned. But in such Ter Meer patent, the overall length of the latch housing or casing must be increased, for example, over that shown in the previous Dexter Patent #1560,- 898, which uses a single spring with the latch bolt. A single spring is too strong for easy and certain door closing without slamming the door, if it is to be sufiiciently strong to hold a bolt against frequent accidental retraction and unlatching of the door.

The present invention by a novel, practical structure retains all of the beneficial results and functions of the Ter Meer patented structure, with a reduced length of the outer casing. If the minimum width of a door stile is 3", and the length of the latch housing in the Ter Meer patent must be 2 there is left only of the 2 :full'thickness of thedoor style when the latch is installed. Reduction of 2 /2" length adds the amount of the full thickness of the door stile retained. Furthermore, :in the practical manufacture of the outside casing, or housing, for the latch, which is done by drawing the relatively deep cylindrical housing that is used, a decrease in the length of the housing, not only uses less material, but the housing will be more easily and economically produced, is better, and not nearly so many are defective and cannot be used as when the latch housing is of the greater length. A better structure, with economy of manufacture, durability and a shorter length latch are of great importance in conjunction with the lighter weight stiles of light doors, with which the latch is most. generally used.

An understanding of the invention may be had from the following description taken in connection with the accompanying drawing in which:

Fig. l is a plan view and partial section showing the latch in plan installed at the vertical edge o f a door frame.

Fig. '2 is a longitudinal, horizontal section through the latch housing or casing with the latch mechanism within shown in plan.

Fig. 3 is a. longitudinal, vertical section through the latch.

Figs. 4, 5, 6 and 7' are transverse, vertical sections on the planes of lines 4-4, 5--5, 6-6 and "l'-l respectively in Fig. v3 looking in the directions indicated by the arrow.

Fig. 8 is a somewhat enlarged perspective view of the latch bolt-retractor and,

Fig. 9 is a fragmentary elevation with some parts broken away, showing the manner of assembly of the retractor with the keeper engaging bolt.

Like reference characters refer to like parts in the difierent figures of the drawings.

The latch of my invention is installed at the free vertical edge of a. door, shown at I of Fig. 1, which has a cylindrical opening 2', bored from such edge inwardly the necessary distance. A transverse opening 3 is also bored through the door toward the inner end of the opening .2. The opening 2 is to receive the latch housing within which the latch bolt and retractor mechanism is mounted, and through the transverse opening 3 an operating spindle is passed which goes through the latch also, and is connected with the interior latch mechanism for retracting the bolt.

In the latch structure disclosed, a cartridgelike housing 4 of cylindrical form is drawn, having an open end at which the metal is turned outwardly in a narrow, annular flange 5. In practice, the inner end of the housing is closed, as at 6, but a closed end, in the present invention, is not necessarily required. A short distance ahead of the end 6, openings 1 are made in opposite sides of the housing for the passage of the spindle.

A latch bolt 8, is mounted for slldable movement at the outer end of the housing 4. Its outer end portion is of a cylindrical form, rather closely fitting the interior of the housing and beveled at its outer end. It includes an inner cylindrical section 9 of a smaller diameter than the larger, or head, part of the bolt. The latch bolt is bored axially from its inner end nearly to its beveled outer end, providing a cylindrical opening I lengthwise of the bolt which is open at its inner end. The inner end portion of the bolt is slotted across at a diameter of the bolt, providing the somewhat elongated slots II, one at each side of the axial opening I0 and directly opposite each other. Near the inner end of the reduced diameter section 9 a continuous annular groove is cut around the bolt, in which a split ring I2 is received, the outer surface of which is flush with the surface of the part 9 of the bolt. A light strength coiled compression spring I3 is located in the axial opening or boring III.

The retractor, best shown in Fig. 8, has a main portion, made from a single plate of flat metal with a space or opening I4 at its rear between parallel flanges I5 turned at right angles from the body to the metal. The flanges I5, at their rear ends, are turned in towards each other in terminal tongues I6 against the back of a body I1, grooved at its opposite sides for receiving the rear end portions of the flanges I5, and at its front formed with a wedge having two sides I8, coming substantially to a point and located at an angle to each other as shown. The plate of metal from which the forward portion of the rectractor is made, in front of the opening I4, is laterally ofiset for a short distance, at I9, slightly in front of the front ends of the flanges I5, and then continued in an arm which terminates in a generally T-head 2I, with two projecting fingers 2Ia and 2Ib at opposite edges of the arm 20, the first of which is longer than the second. The forward edge of the head 21, preferably is of curved form as shown.

A coiled compression spring 22 of a greater strength than the light spring I3, is located around the arm 20, its rear or inner coil bearing against the shoulders provided at the front ends of the flanges I5, and against the inner edges of the fingers 2Ia and 2Ib of thehead 2I at its front end. The retractor is assembled with the latch bolt, after the lighter spring I3 has been placed in the axial opening III, by passing the longer finger 2Ia through the ring I2 (Fig. 9) and moving it upwardly as far as it will go, whereupon the other finger 2lb will pass within the opposite side of the ring I2, after which the retractor may be located in axial alinement with the bolt. The rear end of spring I3 bears against the outer edge of the head 2 I.

As thus assembled, the latch bolt and retractor are entered into the open end of the housing 4 (Fig. 3). Two pairs of spaced indentations 23 are made at opposite sides of the housing, which serve as guides for the flanges I5 passing between them, and as stops or abutments for the inner coil of the heavier spring 22 (Fig. 2).

The latch is completed by a transverse spindle 24, which, at its middle portion, has a V-shaped trough 25 with sides of the trough substantially conforming to the inclined sides I8 of the body IT. The spindle is passed through the opening 3 in the door and the side opening I in the housing, and also passes between the spaced arms I5 of the retractor at the opening I4 between them. When the spindle is located in place, the spring .22 may be shortened a short distance by compression thereof so as to hold the body I! snugly in the trough section 25. The ends of the spindle may have applied thereto a detachable handle 26 and knob 21, one at each end; though, of course, two knobs or two handles may be used so far as the invention is concerned.

When a door with the latch installed thereon, as in Fig. 1 is closed, the beveled end of the bolt head 8 rides over the usual strike plate and the bolt is forced inwardly. It alone moves, the light spring I3 being compressed between the bottom of the axial opening II) and the abutment provided by the head 2|. The inner reduced diameter section 9 of the bolt and the split ring I2 move-within the coils of the spring 22. The strength of the spring 22 is sufficiently greater than that of the spring I3, that the transmission of the force of the spring I3 through the head 2I to the spring 22 does not further appreciably compress the spring 22, therefore, the retractor is held against movement.

When the door is to be opened by retracting the bolt from the keeper on a door jamb provided to receive the projecting end of the bolt head 8, spindle 24 is turned in either direction by the handle 26 or knob 21. The camming action of the trough 25 against the inclined sides of the body I'I moves the retractor inwardly. Spring 22, at its inner end, bearing against the fixed abutments 23, the inward movement of the retractor causes such spring to be compressed as the fingers 2Ia and 2Ib of the head 2| move the outer coils of the spring toward the innermost fixed coil. The fingers of the head 2I in front of the ring I2 engage thereagainst and with a longitudinal inward movement of the retractor, move the bolt, together with the spring I3 to retracting the bolt and disengaging it from its keeper.

The thickness of the metal used in the forward plate portion of the retractor is slightly less than the width of the slots II. The bolt is therefore guided by the cooperative engagement of the sides of the slots with the fingers of the head 2| and by the cooperative engagement of the cylindrical surface of the smaller character section 9 of the bolt within the coils of the heavier spring 22. By the guidance of the indented portions 23 of the housing, and also by the engagement of the trough 25 of the spindle with the body H, the retractor is held from turning about the longitudinal axis of the cylindrical housing 4; and the retractor being thus held, the bolt is held from turning about its longitudinal axis, so that the beveled side of the head 8 of the bolt is always maintained in proper position relative to the strike plate which it is to ride over when the door is closed. The shortening of the outer housing 4 is attained as there need be only a space between the inner end 6 of the housing and the rear sides of the tongue I6 sufficient to permit the required throw of the bolt, that is, the distance it must be retracted to disengage from its keeper. The tongues, coming against the outer portions of the bottom 6 of the housing, limits the inward movement of the retractor so that the spindle cannot be turned through a full revolution.

The structure described is practical and useful, having all desired functional objects of use, the light and heavy springs being compressed, the one only when the door is closed, and the other only when the door is opened. Economy of manufacture, speed and economy of assembly of the bolt and retractor, and of the assembled mechanism with the housing and spindle are present. Large quantity production at low cost is obtained.

The invention is defined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. In a latch structure a bolt of generally cylindrical form having an inner end portion of reduced diameter, said bolt being axially bored from its inner end toward, but short of its outer end and diametrically slotted from its inner end outwardly for a distance, a coiled spring of light strength housed within the bolt, a retractor of fiat metal having a generally T-head at its outer end, slidably received in the slots of said bolt and bearing against the inner end of the light strength spring, means connected with the bolt at the front of which the head at the outer end of the retractor is located, and a heavier coiled compression spring located around the outer portion of the retractor having the {rent coil thereof against the rear side of said head of the retractor, and said retractor at an intermediate portion having abutments against which the inner end coil of the heavier spring engages, the diameter of the inner end portion of the bolt being less than the interior diameter of the coils of the heavier spring.

2. A structure as defined in claim 1, and a cylindrical housing having an open end in which said retractor, bolt and spring are freely inserted, said housing between its ends havingportions extending inwardly against which the inner end coil of said heavier spring engages on moving the retractor and bolt longitudinally of the housing to retract the bolt.

3. In a latch, a latch bolt of cylindrical form having an outer cylindrical head and an inner cylindrical portion of less diameter than the head, said bolt having an axial opening from its inner end outwardly toward, but short of, the outer end of the bolt head, and said bolt being diametrically slotted from its inner end outwardly for a distance, a ring connected to and located around the bolt adjacent its inner end, having an exterior diameter substantially the same as the exterior diameter of the inner end portion of the bolt, a retractor comprising a fiat member including a substantially T-shaped outer portion, comprising a shank in axial alinement with the bolt and oppositely extending fingers at the front end of the shank, said fingers being located at the front of said ring, and the distance between the end of said fingers being substantialy equal to the diameter of said bolt head, said retractor at the rear end of the shank being wider than said shank, the width inward of the shank being substantially the same as the diameter of the bolt head, thereby providing two diametrically opposed shoulders substantialy at right angles to the length of the retractor, a coiled spring of light strength housed within the bolt against the inner end of which the head of said retractor bears, and a second coiled spring of greater strength, the exterior diameter of which is substantially the same as the diameter of the bolt head and the interior diameter of which is greater than the exterior diameter of the inner portion of the bolt, said spring surrounding said shank of the retractor and bearing at its rear end against said shoulders, and at its front end passing over the rear end portion of the bolt and bearing against the rear edges of said head on the retractor.

4. A construction as defined in claim 3, said retractor at the inner end of the shank having laterally extending flanges located in planes substantially at right angles to the plane of the shank, the front ends of which provide said shoulders, said flanges extending rearwardly and being spaced from each other.

5. A construction as defined in claim 3 and a cylindrical housing having an open end into which said retractor, bolt and springs are slidably insertable and means forming a part of the housing extending inwardly back of the innermost coil of the heavier spring.

6. A construction as defined in claim 3, said shank having a longitudinal edge thereof parallel to the axis of the bolt and the opposite longitudinal edge inclined at an angle thereof, said shank progressively decreasing in width toward said fingers, and one of said fingers extending from the shank a greater distance than the other, and the outer end of said head of the shank having arcuate form.

7. A latch having a tubular casing open at its forward end, a latch bolt slidable in said casing, a retractor slidable within said casing, means for sliding the retractor, a chamber in said latch bolt having an opening at the rear end thereof, trans verse slots in said latch bolt at opposite sides of said chamber, detent members extending across said slots, a forward extension on said retractor, said extension having a T-head located in said slots forwardly of said detents, the distance between one tip of said T-head and the opposite edge of the extension at its joinder with the T- head being less than the distance between said detents, a spring in said chamber bearing against the forward side of said T-head and a spring surrounding said retractor extension and bearing against the rear side of said T-head.

8. In a latch structure, a cylindrical housing having an open end, a latch bolt at the open end of the housing normally extending partially outward therefrom, a light spring housed within the latch bolt, a retractor against the outer end of which such light springbears slidably connected with the bolt, whereby the bolt may be moved inwardly without movement of the retractor, means connecting the latch bolt and retractor for bodily withdrawing the bolt and the spring housed therein on inward longitudinal movement of the retractor, a heavier spring around the outer portion of the retractor having its outer end bearing against the front end portion of the retractor, and its inner end held in fixed relation to said housing to prevent the inner end of the spring from movement inwardly within the housing, said bolt at its inner end portion being diametricaly slotted from its inner end toward its outer end, and said retractor at its front end portion being slidably received in said slots, the inner end portion of said bolt beingreduced to a diameter less than the inside diameter of the housing, and said stronger spring comprising a coiled spring, the inner diameter of the coils of which is greater than the diameter of the inner portion of said latch bolt, said latch bolt and lighter spring housed therein being telescopically received within the stronger spring.

ALBERT F. LICK'IEIG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,871,633 Ter Meer Aug. 16, 1932 2,423,988 Lickteig July 15, 1947 

